834 



CHAP. XVIL 



On the Formation of Coral Islands. 



THE production of the Coral Islands of the great 

 Pacific ocean, which endanger this navigation and 

 that of the Indian Archipelago, and are tending fast 

 to destroy that of the Red sea, is a fact completely 

 distinguished from all other subjects of geological 

 investigation. It also forms a most interesting and 

 necessary branch of the present inquiries ; and it is 

 the more indispensable to examine it, because it has 

 hitherto been unaccountably neglected by geological 

 writers. In the case of other submarine animal 

 formations, the results are limited to the germs of 

 future and far distant continents, as the works are 

 without apparent design. But the operations of the 

 coral animals are very different. By their own efforts, 

 assisted by some incidental causes, they build their 

 works above the level of the ocean during their own 

 lives; thus forming rocks and islands, without the 

 necessity of those actions which have raised all the 

 other submarine strata from below. In this manner 

 is the habitable surface of the earth extended, and 

 new regions arise in the ocean. The silent and 

 unnoticed operations of the minutest animals of 

 Creation, are daily preparing the foundations of 

 land, beneath it, destined to extend the dominion 

 of man over a far wider range. 



But the volcanic agencies which form the subject 

 of a former chapter, are frequently found to succeed 

 to these; thus accelerating their results, elevating 

 high above the water that which would otherwise 

 have for ever remained but little raised beyond its 



